The strike also had a major impact in the southern state of Kerala, another left-wing stronghold.

In the capital, Delhi, riot police were deployed at airport terminals.

"The morning roster staff have all reported for duty," an airports spokesman said.

But reports said there were fewer passengers than normal.

The BBC's Monica Chadha in Mumbai says more than five million federal and state government employees in western Maharashtra state participated in the strike.

Public transport services in Mumbai (Bombay) were not affected, but government offices and banks worked with fewer staff.

'Warning'

Many bank workers also stayed at home to protest against foreign investments in pension funds.

"This will be just a warning for the government," said MK Pandhe, general secretary of the Centre of Indian Trade Unions (CITU).

"Unless the government undertakes a comprehensive review of its policies, we will call for a much bigger action - we may go for longer strikes," he added.

India's communist parties have been leading protests across the country against the government's economic policies.

They oppose the government's policy of selling off some of its stake in state-owned corporations to raise funds for investment, privatisation of airports and allowing foreign investment in pension funds.

India's coalition government, led by the Congress Party, relies on four left-wing parties to maintain its majority in parliament.